| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 55419 | Catalysis Today | 2012 | 5 Pages |
Rhodium nanoparticles (Rh NPs) stabilized by phosphine functionalized ionic liquids (FILs) were prepared in [BDMI]NTf2 (BDMI = 1-butyl-2,3-dimethylimidazolium, NTf2 = bis(trifluoromethanesulfonyl)imide) using H2(g) (4 bar) as a reducer. Rh(allyl)3 was used as a “salt-free” Rh NP precursor and allowed to enhance the stability of the Rh NPs compared to the usual RhCl3 precursor. The synthesized FIL stabilized Rh NPs proved to be active biphasic catalysts for the hydrogenation of toluene, styrene and xylenes under mild conditions (75 °C, 40 bar H2(g), 3 h). The impact on activity of the length of the spacer between the phosphine function and the ionic liquid moiety in the FIL was studied. The Rh NPs stabilized by FILs showed higher catalytic activity and recyclability than NPs synthesized in the absence of a stabilizer and more stable than the system employing triphenylphosphine (PPh3) as a stabilizer. The size of the stabilized Rh NPs was measured to be around 2 nm by TEM, while those produced in the absence of a FIL stabilizer formed only aggregates.
Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (114 K)Download as PowerPoint slideHighlights► Rhodium nanoparticles stabilized with phosphine functionalized ionic liquids (FIL) were synthesized using H2 as a reducer. ► These particles proved active for the complete hydrogenation of toluene, styrene and xylenes with excellent to good yields, in an ionic liquid solvent. ► Two precursors of rhodium, Rh(allyl)3 and RhCl3 are used for making the particles and Rh(allyl)3 provided more active and sustainable particles. ► FIL stabilized nanoparticles were more efficient towards hydrogenation than the same particles produced in absence of stabilizer, in an ionic liquid solvent. ► FIL stabilized nanoparticles were as active as particles produced with PPh3 as a stabilizer, but the latter one proved to cause PPh3 leaching in the reaction product.
